A first type of roof box is of a traditional type, and comprises: a hollow body of a parallelepiped shape, which can be positioned on the roof rails of a motor vehicle and is provided with an opening through which it is possible to access his inner space intended for luggage; a lid, which is hinged to the top of the hollow body and is movable from a closed position, in which the lid closes the opening, to an open position, in which the lid does not obstruct the opening, and vice versa; fastening means for fastening, detachably as needed, the hollow body to the roof rails of a motor vehicle. However, this well-known type of roof box has proved to be unsuitable for carrying luggage on the roof of a vehicle, since its square shape causes problems of aerodynamics. Furthermore, due to the considerable height from the ground at which is positioned the opening of the hollow body, it is difficult to load the luggage into the inner space of the hollow body, so for this purpose it is almost always necessary to disassemble the roof box from the roof.
In order to overcome the problems of aerodynamics and also to facilitate access to the space intended for luggage, a second type of roof box has been developed with a more aerodynamic shape, in particular a longer and lower shape. These well-known aerodynamic boxes differ from the first type, previously described, in that in place of the hollow body and the lid, there are two half-shells, which are arranged one above the other, enclose the space intended for luggage and are reciprocally movable, to make the luggage space accessible. More particularly, one of the two half-shells, the lower one, is fixed to the vehicle roof rails, while the other, the upper half-shell, is hinged to the fixed half-shell, and can therefore be rotated, with respect to the fixed half-shell, from a closed position, in which it rests on the underlying fixed half-shell, to an open position, thanks to which the space between the two half-shells is made accessible, and vice versa. When the roof box is opened, the movable half-shell, i.e. the upper half-shell, is rotated upwards, while when the roof box is closed, the movable half-shell, i.e. the upper half-shell, is rotated downwards. In the case of this second type of roof box, however, the fact that the space intended for luggage is enclosed by two mutually movable shells, undermines a complete exploitation of this space, since in the open position of the roof box the walls that contain the luggage laterally are only those of the fixed half-shell, i.e. the lower one. This second type of roof box also presents a loading difficulty due to the height from the ground, since to close the movable half-shell that is in the open position it is necessary to climb, keeping the car door open, at least onto the vehicle floor or even onto the seat and stretch over the roof to grasp the edge of the movable half-shell and pull it down.
Documents U.S. Pat. No. 2,812,992 A, GB 119331 A and US 2007/164066 A1 concern and show a third known type of roof box, in which the opening is arranged on a lateral side of the hollow body. It is possible to access from the side the inner space intended for luggage and no longer from the top as provided for in the other known types of roof box, which greatly facilitates the accessibility to this inner luggage space, since the height to which luggage must be lifted is greatly lowered and it is also possible to look inside this inner space to see how much space is available.
The lateral side in which the opening is arranged is a longitudinal lateral side of the hollow body. In this case the flap can be large-sized, which further increases the accessibility to the inner space of the hollow body without compromising the full exploitation of the inner space.
The roof box of the above-mentioned document U.S. Pat. No. 2,812,992 A also has a plurality of bodies, which are located inside the hollow body and on which the luggage containers can be placed in a removable manner. Since, starting from the bottom of the hollow body, these bodies extend upwards and protrude into the inside of the hollow body, the luggage cannot be placed directly on the bottom of the hollow body.
Document DE 3419430 A1 shows a further known roof box of the aforementioned third type, in which it can be seen that the opening can also be in a transverse lateral side of the hollow body. In this case it is possible to insert into the roof box objects that are as long as the roof box, with extreme ease and from the side.